The steam-engine was created by talented inventors. Some of them had engineering education, many were mechanics self-educated persons, and others had no relation to the equipment at all, but once "having got sick" with the steam-engine, completely gave themselves to hard inventive work.
It were people of a practical warehouse. Most of them represented a little what occurs in the steam-engine to what laws its work submits. They did not know the theory of heat engines and as now would tell, invented in the dark, to the touch. Many understood it and first of all supporters of scientific approach to creation of cars.
The founder of this theory which laid the foundation for the science called "thermodynamics" became — Sit down Carnot who later after the provided statements of the father wrote forty years the small brochure under the name: "Reflections about the driving force of fire and about the cars capable to develop this force". This thin book was published in Paris in 1824 by small circulation. Sit down Carnot that year executed as early as twenty eight years. The book was the only composition Sit down Carnot so surprising by the composition and considerable, as well as her author. Sit down Carnot was born in 1796 and up to sixteen years studied under the leadership of the father who managed to impart to the son breadth of views and tendency to the exact sciences at home. Then the talented young man studies two years at the Parisian polytechnical school and in eighteen years gains the diploma of the engineer. Further life and activity Sit down it was connected with army. Having a lot of free time, he could be engaged in everything that interested him. And interests it were extensive. He knew and loved art — music, literature, painting, theater, and at the same time passionately was fond of mathematics, chemistry, physics, technology. Since early childhood it developed tendency to generalizations — ability behind the separate facts and the phenomena to see something the general, uniting them. Being an engineer, he well knew the device of the steam-engine and saw all its shortcomings clearly. He understood that still creators of the steam-engine thought a little of laws which operate thermal processes. At the same time during creation and improvement of the steam engine many facts, nobody yet not thought over and not generalized collected.
The young engineer sets before himself the purpose to understand the thermal phenomena occurring in the steam engine, to try to output the general laws to which operation of the heat engine submits. And he to the first manages to make it. Sit down Carnot undoubtedly, was an outstanding identity of the time though his contemporaries and he did not suspect it. For the first time the world learned about his merits many years later from the statements of the great English physicist William Thomson (lord Calvin) who at the lectures called Carnot the ingenious scientist. Subsequently Thomson and the outstanding German physicist Rudolf Klauzius, creating modern thermodynamics, generalized conclusions, Sit down Carnot in the form of the strict law which received the name of the second beginning of thermodynamics.
About what did Carnot write in the thin book which brought him undying glory? Carnot considered in it laws of transformation of warmth into work, or as speak, laws of transformation of thermal energy in mechanical, and showed how it is necessary to build heat engines that they were more powerful and at the same time economic, that is would consume as little as possible fuel. Its conclusions were the general and concerned not only piston steam-engines known to him, but in general any engines using thermal energy for the work. First of all, he established that heat can pass only "... from a body with more high temperature to a body with less high temperature..." and, when temperature of both bodies will even out, there comes thermal balance. Further, heat can be turned into mechanical work if on the way of heat to put any device in which a part of this passing heat would be used, for example, for expansion of steam or gas moving the piston. At the same time the greatest number of useful work can be received in case the difference of temperatures of bodies between which there is a transition of heat is the greatest. Then Carnot draws a conclusion: any heat engine in which heat turns into mechanical work has to have two temperature levels — top (heat source) and lower (cooler condenser); besides, in such engine there has to be a substance — it can be not obligatory steam — capable to change the volume when heating and cooling and by that to turn heat into mechanical work, moving the piston in a cylinder. Such substance is called "a working body". In order that the steam engine made the greatest mechanical work, it is necessary that temperature and pressure of a working body — steam entered into a cylinder were as it is possible big, and temperature and pressure of vapor which is taken away in the condenser — the smallest. Besides, Carnot specified how it is better to bring heat to a working body as it is better to expand this working body as it is better to take away from it heat and as it is better to prepare a working body for expansion again. These instructions were so exact that if it was succeeded to construct the heat engine working according to Carnot's recommendations — such engine would be ideal: in it almost all heat upon transition from a source to the cooler would turn into mechanical work, without being lost on heat exchange with the environment. Such operation of the engine is called in thermodynamics work on an ideal cycle of Carnot. On that how far operation of any heat engine deviates work on Carnot's cycle, judge perfection of this engine: the more the cycle of the engine is similar to Carnot's cycle, the better in such engine the warmth is used.
Together with the small book Sit down Carnot in life the new science — science about warmth entered. Creators of heat engines became "sighted people". They could already design heat engines with open eyes, without groping to the touch the way in the dark. In their hands there were laws under which it is necessary to build engines. These laws formed the basis of improvement not only steam-engines, but also all heat engines for many years ahead up to our days. Life of this talented French engineer and scientist broke very much early. He died of cholera in 1832, thirty six years old. All its personal property including the most valuable workbooks, it was burned. Sit down Carnot left to mankind only one small book, but also it it was sufficient to make his name immortal.